Device and method for testing penetration depth of wellbore fluid into reservoir

Abstract

The invention discloses a device for testing the penetration depth of wellbore fluid into a reservoir. The device mainly solves the problem that data obtained by a testing technology and method in the prior art cannot truly and effectively reflect the actual well bottom working condition. The device comprises a double-core holder, a formation pressure simulation mechanism, a formation temperature simulation mechanism, a liquid circulation mechanism and a flow measurement mechanism which are respectively connected with the double-core holder through pipelines, and a data processing mechanism for receiving and processing data information in the double-core holder. By means of the scheme, the working conditions and reservoir environments under different construction operation conditions in the oil-gas exploration and development process can be simulated, and the depth of shaft liquid invading the reservoir is continuously measured through microwaves; the method provides a basis for optimization of wellbore fluid performance and system optimization, and selection and design of engineering processes such as drilling parameters, well completion modes, reservoir transformation technologies, reservoir protection technologies and the like, and has high practical value and popularization value.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploration and development. Specifically, it relates to a testing device and a testing method for the depth of wellbore fluid invading into a reservoir. Background Art

[0002] During the process of oil and gas exploration and development, the reservoir will come into contact with different wellbore fluids at different construction stages, such as drilling fluid, kill fluid, cement slurry, well flushing fluid, fracturing fluid, etc. Due to the action of positive pressure difference and capillary pressure, the wellbore fluid will invade the reservoir through pores and fractures. On the one hand, it forms a liquid-phase blockage in the pores, and on the other hand, it undergoes various physical and chemical reactions with the rock and fluid to form precipitates or flocs that block the pore throats, which will inevitably affect the seepage ability of the reservoir rock, cause reservoir damage, and affect the productivity of oil and gas wells. The invasion depth of the wellbore fluid determines the scope of the reservoir damage zone, and the size of the damage zone provides an important reference for the decision-making of reservoir protection in the early stage of construction operations and damage removal in the later stage. Only by accurately testing and evaluating the invasion depth can we optimize the performance of the wellbore fluid and select the optimal system, and provide reliable technical support for the selection and design of engineering technologies such as drilling parameters, completion methods, reservoir stimulation technologies, and reservoir protection technologies, which is of extremely important significance for the effective exploration and efficient development of oil and gas reservoirs.

[0003] The invasion depth of the wellbore fluid into the reservoir is affected by various factors, mainly including: reservoir characteristics (such as pore structure, permeability, filling material, pore pressure, pore fluid, temperature, etc.). Wellbore fluid properties (such as viscosity, density, filtration loss performance, solid particle size distribution and total content, etc.), engineering parameters (such as pump pressure, bottom-hole flowing pressure, construction duration, etc.). Only by simulating the actual conditions of the reservoir, engineering, fluid, etc. as comprehensively and realistically as possible can we truly reflect the depth of the wellbore fluid invading into the reservoir.

[0004] Currently, the industry pays more and more attention to the research on the invasion depth of wellbore fluid, and relevant research results have been reported frequently. For example, "A Drilling Fluid Leakage Damage Simulation Device and Method" (publication date: March 8, 2022, publication number: CN114152555A), "A Quantitative Testing Device and Method for the Degree of Coal Seam Pollution during Horizontal Well Drilling" (publication date: February 24, 2020, publication number: CN 111175217A), "A Testing Device and a Testing Method for the Invasion Depth of Drilling Fluid" (publication date: April 27, 2018, publication number: CN107965310A), etc. disclosed in Chinese patent documents.

[0005] Although these test methods and techniques can all, to a certain extent, measure the invasion depth of fluids into the reservoir, they have deficiencies during the tests. For example, the test cores used cannot reflect the true situation of the reservoir. For instance, when using a sand-packed tube as the experimental core, there are significant differences in the rock particle types and pore structures between it and the reservoir rock; or using natural cores that are too short (less than 10 cm), and the core length is much lower than the invasion depth of the wellbore fluid into the reservoir. Additionally, the actual downhole conditions that determine the invasion depth, such as liquid column pressure, pore pressure, temperature, etc., are not fully simulated; the detection of the invasion depth mostly uses the direct measurement method. On the one hand, the surface invasion state cannot truly reflect the overall invasion characteristics of the fluid, and on the other hand, loading and unloading the core during the experiment increases systematic and human errors. Therefore, the data obtained through the existing test methods and techniques cannot truly and effectively reflect the characteristics of the wellbore fluid invasion depth under actual bottomhole working conditions. Summary of the Invention

[0006] The purpose of the present invention is to provide a test device and test method for the invasion depth of wellbore fluids into the reservoir, mainly to solve the problem that the data obtained by the existing test methods and techniques cannot truly and effectively reflect the characteristics of the wellbore fluid invasion depth under actual bottomhole working conditions.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A test device for the invasion depth of wellbore fluids into the reservoir includes a double-core holder, a formation pressure simulation mechanism, a formation temperature simulation mechanism, a liquid circulation mechanism, and a flow measurement mechanism that are respectively connected to the double-core holder through pipelines, and a data processing mechanism for receiving and processing data information in the double-core holder;

[0009] The double-core holder includes a plug, and a holder housing that is threadedly connected to the plug to form a seal and has a double-cavity structure. Among them, the double-cavity structure is interconnected through a channel, and the plug is provided with four channels connected to the pipelines.

[0010] Further, two cores are placed in the double cavities of the holder housing. Among them, independent annular gaps are formed between the cores and the inner surface of the cavities of the holder housing, and pipeline channels are respectively provided in the annular gaps to connect to the formation pressure simulation mechanism.

[0011] Further, the formation pressure simulation mechanism includes a nitrogen cylinder and a gas booster pump connected to the double-core holder through pipelines, a pressure gauge 1 and a valve 1 with one end of the pipeline connected to the gas booster pump and the other end passing through the plug, and a pressure gauge 2 and a valve 2 with one end of the pipeline connected to the gas booster pump and the other end passing through the holder housing. Among them, the pipelines extend from the nitrogen cylinder to the independent annular gaps formed between the cores and the inner surface of the cavities in the double-core holder and the independent spaces formed between the plug and the core end faces respectively.

[0012] Further, the liquid circulation mechanism includes a liquid tank, a circulation loop pipeline with one end connected to the liquid tank and both the liquid supply pipeline and the liquid return pipeline connected to the plug and the core end face, a liquid booster pump and a valve four installed on the liquid supply pipeline, and a valve three and a pressure gauge three installed on the liquid return pipeline; wherein, the liquid supply pipeline of the circulation loop pipeline extends from the bottom of the liquid tank to the independent space formed by the plug and the core end face, and the liquid return pipeline of the circulation loop pipeline extends from the independent space formed by the plug and the core end face in the double-core holder to the top of the liquid tank.

[0013] Further, the flow rate measuring mechanism includes a liquid flow rate measurer connected to the plug through a pipeline, a pressure gauge four installed on the pipeline connecting the liquid flow rate measurer and the plug, a gas flow rate measurer connected to the liquid flow rate measurer through a pipeline, and a valve five installed on the pipeline connecting the liquid flow rate measurer and the gas flow rate measurer, wherein the pipeline extends from the liquid flow rate measurer to the independent annulus formed by the core and the plug.

[0014] Further, the formation temperature simulation mechanism includes a temperature controller, a heater one and a heater two with one ends connected to the temperature controller through wires at the same time and the other ends respectively placed on the inner surfaces of the double cavities of the holder housing.

[0015] Specifically, the data processing mechanism includes a data analyzer, an ultrasonic generator connected to the data analyzer through a data line and fixed at the central position of the holder housing, an ultrasonic receiver one and an ultrasonic receiver two connected to the data analyzer and the ultrasonic generator through data lines at the same time and respectively fixed in the double cavities of the holder housing, wherein the ultrasonic receiver one and the ultrasonic receiver two are elastic so as to be fixed and closely attached to the core, and make the core closely attached to the ultrasonic generator, and a plurality of the ultrasonic receiver one and the ultrasonic receiver two are arranged at intervals in the double cavities of the holder housing.

[0016] A test method for a test device of the invasion depth of wellbore fluid into the reservoir is as follows:

[0017] Step 1. Put two cores into the holder housing, adjust the positions of the cores to ensure that the ultrasonic generator, the ultrasonic receiver one and the ultrasonic receiver two are closely attached to the cores;

[0018] Step 2. Press and seal the cores in the double-core holder with plugs;

[0019] Step 3. Set the temperature controller according to the actual formation temperature, heat the cores and keep them at a constant temperature to simulate the formation temperature environment;

[0020] Step 4. According to the actual formation pressure, use a nitrogen cylinder to pressurize and stabilize the pressure through the formation pressure simulation mechanism to simulate the formation pore pressure environment;

[0021] Step 5. Turn on the ultrasonic generator, ultrasonic receiver 1, and ultrasonic receiver 2, and turn on the data analyzer;

[0022] Step 6. According to the actual working conditions, load the wellbore fluid into the fluid tank, set the pump pressure according to the actual bottom-hole liquid column pressure, and turn on the liquid booster pump to circulate the fluid;

[0023] Step 7. Collect data in real time through the probes at different positions of ultrasonic receiver 1 and ultrasonic receiver 2, calculate the lateral change of core density through the data analyzer, and measure the depth of wellbore fluid invading the core;

[0024] Step 8. Read the data of the liquid flow meter and gas flow meter, and calculate the corrected invasion depth according to the volumes of the liquid and gas and the pore volume of the core.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention simulates a reservoir with a longer depth by connecting two natural cores in parallel, and as much as possible truly simulates the main factors affecting the invasion of wellbore fluid into the reservoir, such as the flow state of wellbore fluid, liquid column pressure, and formation temperature. Use a multi-probe ultrasonic receiver to monitor the change of core density in real time, so as to more truly and effectively measure the depth of wellbore fluid invading the reservoir. The measurement results are for the optimization of wellbore fluid performance and the selection of systems; it has more reference value for the selection and design of engineering technologies such as drilling parameters, completion methods, reservoir stimulation technologies, and reservoir protection technologies.

[0027] (2) The present invention can fully simulate the actual downhole conditions and continuously obtain the test of the invasion depth of different wellbore fluids into the reservoir, and truly reflect the characteristics of the invasion depth of wellbore fluid under the actual bottom-hole working conditions.

[0028] (3) A number of ultrasonic receivers are arranged in the present invention, usually one is set every 5 cm. The purpose is to better monitor the change of core density in the longitudinal direction, so as to more accurately measure the depth of wellbore fluid invading the core.

[0029] (4) The test device of the present invention is simple and convenient to install, fix and disassemble, and the principle of the test method is simple, easy to operate and popularize. Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the present invention.

[0031] Figure 2 is Figure 1Side view at A-A in the figure.

[0032] In the above-mentioned drawings, the component names corresponding to the reference numerals are as follows:

[0033] 1 - Double core holder; 11 - Plug; 12 - Holder housing; 2 - Formation pressure simulation mechanism; 21 - Nitrogen cylinder; 22 - Gas booster pump; 23 - Pressure gauge 1; 24 - Valve 1; 25 - Pressure gauge 2; 26 - Valve 2; 3 - Formation temperature simulation mechanism; 31 - Thermostat; 32 - Heater 1; 33 - Heater 2; 4 - Fluid circulation mechanism; 41 - Valve 3; 42 - Pressure gauge 3; 43 - Fluid tank; 44 - Valve 4; 45 - Liquid booster pump; 5 - Data processing mechanism; 51 - Ultrasonic generator; 52 - Ultrasonic receiver 1; 53 - Ultrasonic receiver 2; 54 - Data analyzer; 6 - Flow measurement mechanism; 61 - Liquid flow meter; 62 - Gas flow meter; 63 - Valve 5; 64 - Pressure gauge 4; 7 - Core 1; 8 - Core 2. Specific embodiments

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present invention are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the drawings). If the specific posture changes, the directional indications will also change accordingly.

[0035] In the present invention, unless otherwise clearly defined and limited, the terms "connection", "fixation", etc. shall be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0036] Embodiment, such as Figure 1 And Figure 2As shown in the figure, a testing device for the depth of wellbore fluid invading the reservoir includes a double-core holder 1, a formation pressure simulation mechanism 2, a formation temperature simulation mechanism 3, a liquid circulation mechanism 4, a flow measurement mechanism 6, and a data processing mechanism 5 which are respectively connected to the double-core holder 1 through pipelines.

[0037] Among them, the double-core holder 1 is composed of a plug 11 and a holder housing 12. The holder housing 12 has an upper and lower double-chamber structure, and there is a channel on the right side to connect the double chambers. Cores are placed inside the chambers. The diameter of the core is 10 cm, and the length of a single core is 75 cm. After being connected through the channel, it can meet the testing requirements for the depth of fluid invading the reservoir within a range of 150 cm. The plug 11 is threadedly connected to the holder housing 12 to form a seal. Inner grooves are opened on the upper and lower parts of the plug 11 to form an independent space with the end face of the core. There are two sets of four pipeline channels on the upper and lower parts of the plug 11. The upper two channels are used to connect the liquid circulation mechanism 4 to establish a liquid circulation loop, and the lower two channels are used to connect the formation pressure simulation mechanism 2 and the flow measurement mechanism 6. The ultrasonic generator 51, the first ultrasonic receiver 52, and the second ultrasonic receiver 53 are fixed on the holder housing 12 and connected to the data analyzer 54 through data lines. The first heater 32 and the second heater 33 are respectively arranged on the inner surfaces of the double chambers of the holder housing 12 and connected to the temperature controller 31 through wires.

[0038] The testing steps based on the above device are as follows:

[0039] Step 1. Put two cores with a length of 75 cm and a diameter of 10 cm into the double-core holder 1, adjust the positions of the cores to ensure that the ultrasonic generator 51, the first ultrasonic receiver 52, and the second ultrasonic receiver 53 are closely attached to the cores.

[0040] Step 2. Use the plug 11 to press the cores firmly in the double-core holder and form a seal.

[0041] Step 3. Set the temperature controller 31 according to the actual formation temperature, heat and keep it at a constant temperature to simulate the formation temperature environment.

[0042] Step 4. Set the pump pressure according to the actual formation pressure, start the gas booster pump 22 to pressurize with a nitrogen cylinder and stabilize the pressure to simulate the formation pore pressure environment.

[0043] Step 5. Start the ultrasonic generator 51, the first ultrasonic receiver 52, and the second ultrasonic receiver 53. Start the data analyzer 54.

[0044] Step 6. Load the wellbore fluid into the fluid tank 43, set the pump pressure according to the actual bottom-hole fluid column pressure, turn on the liquid booster pump 45 to circulate the fluid, and simulate the flow state of the wellbore fluid at the bottom hole. The circulation time can be determined according to the actual working condition operation time. For example, when measuring the invasion depth of the drilling fluid, the drilling cycle is used as the circulation time.

[0045] Step 7. Collect data in real time through the probes at different positions of the first ultrasonic receiver 52 and the second ultrasonic receiver 53, and calculate the longitudinal change of the core density through the data analyzer 54 to measure the invasion depth of the wellbore fluid into the core.

[0046] Step 8. Measure the gas and liquid volumes passing through the core through the liquid flow meter 61 and the gas flow meter 62 respectively to calculate the total amount of wellbore fluid invading the core, and calculate the corrected invasion depth according to the liquid volume and the pore volume of the core.

[0047] Through the above device and test method, it is possible to fully simulate the actual downhole conditions and continuously obtain the invasion depths of different wellbore fluids into the reservoir, and truly reflect the characteristics of the invasion depth of the wellbore fluid under the actual bottom-hole working conditions.

[0048] The above embodiments are only the preferred embodiments of the present invention, and do not limit the protection scope of the present invention. Any changes made by using the design principle of the present invention and non-creative labor on this basis shall fall within the protection scope of the present invention.

Claims

1. A device for testing the depth of wellbore fluid intrusion into a reservoir, characterized in that: The invention comprises a double core holder (1), a formation pressure simulation mechanism (2), a formation temperature simulation mechanism (3), a liquid circulation mechanism (4) and a flow measurement mechanism (6) respectively connected to the double core holder (1) via pipelines, and a data processing mechanism (5) for receiving and processing data information in the double core holder (1); The double core clamp (1) comprises a plug (11), and a clamp housing (12) which is threadedly connected to the plug (11) to form a seal and has a double-cavity structure, wherein the double-cavity structure is interconnected through a channel, and the plug is provided with four channels connected to the pipeline.

2. A testing device for the depth of wellbore fluid invading a reservoir according to claim 1, characterized in that: Two rock cores are placed in the double cavity of the clamp housing (12), wherein the rock cores and the inner surface of the cavity of the clamp housing form an independent annular space, and pipeline channels are respectively provided in the annular space to connect the formation pressure simulation mechanism (2).

3. A testing device for the depth of wellbore fluid invading a reservoir according to claim 2, characterized in that: The formation pressure simulation mechanism (2) comprises a nitrogen bottle (21) and a gas booster pump (22) connected to the double core clamp (1) through a pipeline, a pressure gauge (23) and a valve (24) connected to the gas booster pump through one end of the pipeline and passing through a plug at the other end, and a pressure gauge (25) and a valve (26) connected to the gas booster pump through one end of the pipeline and passing through a clamp housing at the other end, wherein the pipelines extend from the nitrogen bottle to an independent annular space formed by the core and the inner surface of the cavity in the double core clamp and to an independent space formed by the plug and the end face of the core.

4. A device for testing the depth of wellbore fluid invading a reservoir according to claim 3, characterized in that: The liquid circulation mechanism (4) comprises a liquid tank (43), a circulation loop pipeline having one end connected to the liquid tank and a liquid supply pipeline and a liquid return pipeline both connected to the plug and the core end face, a liquid booster pump (45) and a valve four (44) installed on the liquid supply pipeline, and a valve three (41) and a pressure gauge three (42) installed on the liquid return pipeline; wherein the liquid supply pipeline of the circulation loop pipeline extends from the bottom of the liquid tank to the independent space formed by the plug and the core end face, and the liquid return pipeline of the circulation loop pipeline extends from the independent space formed by the plug and the core end face in the double core clamp to the top of the liquid tank.

5. A device for testing the depth of wellbore fluid invading a reservoir according to claim 4, characterized in that: The flow measurement mechanism (6) comprises a liquid flow meter (61) connected to the plug via a pipeline, a pressure gauge (64) installed on the pipeline connecting the liquid flow meter and the plug, a gas flow meter (62) connected to the liquid flow meter via a pipeline, and a valve (63) installed on the pipeline connecting the liquid flow meter and the gas flow meter, wherein the pipeline extends from the liquid flow meter to an independent annulus formed by the core and the plug.

6. A device for testing the depth of wellbore fluid invading a reservoir according to claim 5, characterized in that: The formation temperature simulation mechanism (3) comprises a temperature controller (31), two heaters (32) and (33) connected to the temperature controller at one end through a wire and respectively placed on the inner surface of the double cavity of the clamp housing at the other end.

7. A device for testing the depth of wellbore fluid invading a reservoir according to claim 6, characterized in that: The data processing mechanism (5) comprises a data analyzer (54), an ultrasonic generator (51) connected to the data analyzer via a data line and fixed at the center of the clamp housing, and two ultrasonic receivers (52) and (53) connected to the data analyzer and the ultrasonic generator via data lines and fixed in the double cavities of the clamp housing, respectively, wherein the ultrasonic receivers (52) and (53) are elastic so that they can be fixed and tightly attached to the core and the core can be tightly attached to the ultrasonic generator, and a plurality of the ultrasonic receivers (51) and (53) are arranged at intervals in the double cavities of the clamp housing.

8. A method for testing a wellbore fluid intrusion depth test device according to any one of claims 1 to 7, the specific steps being as follows: Step 1. Place two cores into the holder housing, adjust the core positions, and ensure that the ultrasonic generator, ultrasonic receiver 1, and ultrasonic receiver 2 are in close contact with the cores; Step 2. Use a plug to press the core firmly and seal it in the double core holder; Step 3. Set the temperature controller according to the actual formation temperature, heat the core and keep it at a constant temperature to simulate the formation temperature environment; Step 4. According to the actual formation pressure, the formation pressure simulation mechanism uses a nitrogen bottle to pressurize and stabilize the pressure to simulate the formation pore pressure environment; Step 5. Turn on the ultrasonic generator, ultrasonic receiver 1 and ultrasonic receiver 2, and turn on the data analyzer; Step 6. According to the actual working conditions, the wellbore fluid is loaded into the fluid tank, the pump pressure is set according to the actual bottom hole liquid column pressure, and the liquid booster pump is turned on to circulate the fluid; Step 7. The probes at different positions of the ultrasonic receiver 1 and the ultrasonic receiver 2 are used to collect data in real time, and the lateral change of the core density is calculated by the data analyzer to measure the depth of the wellbore fluid invading the core; Step 8. Read the data of the liquid flow meter and the gas flow meter, and calculate the corrected invasion depth according to the liquid and gas volumes and the core pore volume.

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